Full sets of golf clubs are available featuring variations in design and construction which are suited to the individual golfer's physical size and strength. As a minimum, quality factory-made clubs provide for at least the three variables of shaft-flex, over-all length and swing weight. In addition to these three basic variables it is also known to custom fit a set of clubs to the needs of a specific individual golfer by variations in the weight of the club head, the weight of the shaft, the total weight of the club, the loft of the club face, angle of the face of the wood clubs to the shaft (i.e., either open or closed), the club lie and the size and shape of the grip.
Given all of these possible parameters it is obvious that even one club, be it a wood or an iron, could be produced in a limitless number of variations. However, if the specific requirements of a given individual are applied, such as stance, grip, height, and strength, many of these parameters become fixed within narrow ranges and the design specifications for a club can be fixed which will give the golfer a good fit. Having determined the optimum specifications for one club in the set, it is possible to apply these to the other clubs and produce a so-called matched set. The clubs of this matched set are designed to "feel" alike or "swing" alike.
As noted above, the swing weight of a club is one of the variable design parameters to be determined according to the individual golfer's requirements. It is generally accepted that the swing weight of the clubs in a matched set should be the same. The swing weight of a given club is determined by placing the club across a knife-edge or fulcrum located at an arbitrary fixed distance d.sub.sw from the grip end of the shaft and placing sufficient weight at the very tip of the grip end of the shaft to balance the club. This weight is then the swing weight.
It is presently the practice in the industry that the swing weight shall be determined by locating the fulcrum at a distance d.sub.sw of either twelve or fourteen inches from the grip end of the shaft. The older and original method of determining the swing weight was on the Lorythmic scale in which the fulcrum was fourteen inches from the tip of the grip end of the shaft.
The essential element in the game of a golf is control. Control implies that a golfer may achieve predictable and consistent results using the same club to hit the same or equivalent ball. When the swing weights of a set of clubs are properly matched the golfer will experience the same subjective feel in swinging all of his clubs, whether irons or woods. Under these circumstances the golfer is able to develop and master one good swing which need not be varied with each club or type of club he happens to be swinging.
It is therefore an object of our invention to provide a method for improving the dynamic performance characteristics of a golf club and further to provide a method of more accurately matching the clubs in a set so that the clubs swing, or `feel`, alike.
It is a further object of our invention to provide clubs incorporating novel design features which produce dynamic forces during the club swing which aid the golfer in his efforts to control the club movement.